1. Field of the Invention
The present invention relates to occipital and chin supports and more particularly to such supports which effectively fix the distance between the supports in the sagittal plane and prevent translation of the supports in the coronal plane.
2. Description of the Prior Art
Cervical-thoracic poster-type orthoses consist of an occipital support and a chin support attached to chest and/or back plates and it is common practice to connect the chin and occipital supports together by flexible means such as Velcro straps, as is characteristic of the support disclosed in Lerman U.S. Pat. No. 4,628,913. In such supports the straps, when anchored, only prevent the two supports from moving away from each other, i.e. prevent the chin support from moving anteriorly in relation to the occipital support. The flexible strap arrangement however, does not prevent the chin support from moving posteriorly which results in pressure on the patient's Adam's apple. Nor does the flexible strap arrangement prevent upward and downward translation of the chin support in relation to the occipital support. This limitation on the flexible strap connection in preventing cephalad, caudad, as well as posterior translation results in compromised head, and therefore, neck control and poor patient comfort.
Also known is the type of cervical brace disclosed in Nitschke U.S. Pat. No. 3,724,452 where a rigid chin support bar and a U-shaped occipital support bar are both secured to a chest plate, which arrangement often does not give the degree of occipital support desired since the respective supports are interconnected only through the chest plate and the only direct interlock between the occipital support and chin support is a flexible strap. As a result, one research study (see Rollin M. Johnson, MD., et al., "Cervical Orthoses: A study comparing their effectiveness in restricting cervical motion in normal subjects", Journal of Bone and Joint Surgery, Vol. 59A, No. 3, pp. 332-339, 1977), demonstrated that this cervical brace performs poorly in preventing cervical extension.
Another type of known cervical brace is that shown in Schurman U.S. Pat. No. 4,383,523 which discloses a cervical brace with independently adjustable chin and occipital supports which, although said to provide rigid support for each, is quite bulky and awkward to use, being designed for support based on pelvic contact rather than chest and back contact. In addition, although the distance between the chin and occipital supports in this brace can be fixed, the chin support may inadvertently shift cephalad or caudad in relation to the occipital support. This can occur because in this orthosis both the occipital support and the chin support pivot about separate axes on the lateral interlocking members.
McGuinness et al U.S. Pat. No. 4,793,334 discloses a cervical base with a chin support member which can be adjustably fixed either inwardly or outwardly but is without any occipital support.
Veale U.S. Pat. No. 5,005,563 discloses a brace which includes only an occipital support without a chin support and appears to be designed to create cervical traction.
Herman U.S. Pat. No. 5,171,296 discloses a head holding jig that is intended exclusively for use in surgery.